package com.buddy.learn.javasource._collection;

import com.alibaba.fastjson.JSON;
import lombok.Builder;
import lombok.Data;
import org.junit.Test;

import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.stream.Collectors;

/**
 * @author buddy
 * @date 2021/10/29
 */
public class _List {
    @Test
    public void testTree(){
        //模拟从数据库查询出来
        List<Menu> menus = Arrays.asList(
                new Menu(1,"根节点",0),
                new Menu(2,"子节点1",1),
                new Menu(3,"子节点1.1",2),
                new Menu(4,"子节点1.2",2),
                new Menu(5,"根节点1.3",2),
                new Menu(6,"根节点2",1),
                new Menu(7,"根节点2.1",6),
                new Menu(8,"根节点2.2",6),
                new Menu(9,"根节点2.2.1",7),
                new Menu(10,"根节点2.2.2",7),
                new Menu(11,"根节点3",1),
                new Menu(12,"根节点3.1",11)
        );

        //获取父节点
        List<Menu> collect = menus.stream().filter(m -> m.getParentId() == 0).peek(
                (m) -> m.setChildList(getChildren(m, menus))
        ).collect(Collectors.toList());
        System.out.println("-------转json输出结果-------");
        System.out.println(JSON.toJSON(collect));
    }

    private List<Menu> getChildren(Menu root, List<Menu> all) {
        return all.stream().filter(m -> Objects.equals(m.getParentId(), root.getId())).peek(
                (m) -> m.setChildList(getChildren(m, all))
        ).collect(Collectors.toList());
    }
}
/**
 * Menu
 * @author lcry
 */
@Data
@Builder
class Menu {
    /**
     * id
     */
    public Integer id;
    /**
     * 名称
     */
    public String name;
    /**
     * 父id ，根节点为0
     */
    public Integer parentId;
    /**
     * 子节点信息
     */
    public List<Menu> childList;


    public Menu(Integer id, String name, Integer parentId) {
        this.id = id;
        this.name = name;
        this.parentId = parentId;
    }

    public Menu(Integer id, String name, Integer parentId, List<Menu> childList) {
        this.id = id;
        this.name = name;
        this.parentId = parentId;
        this.childList = childList;
    }

}
